Granted Patent
Utility
US 5,247,497 · App. 07/793,561
Security systems based on recording unique identifier for subsequent playback
Inventor:
Robert S. Cohn
Patented Case
View Patent ↗
Granted: Sep 21, 1993
Filed: Nov 18, 1991
Inventor
Robert S. Cohn
Assignee (at issue)
Octel Communications Corporation
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.